The applications of Type B [anisotropic analytical algorithm (AAA) and collapsed cone (CC)] and Type C [Acuros XB (AXB) and photon Monte Carlo (PMC)] dose calculation algorithms in spine stereotactic body radiotherapy (SBRT) were evaluated. Water- and bone-equivalent phantoms were combined to evaluate the percentage depth dose and dose profile. Subsequently, 48 consecutive patients with clinical spine SBRT plans were evaluated. All treatment plans were created using AXB in Eclipse. The prescription dose was 24 Gy in two fractions at a 10 MV FFF on TrueBeam. The doses were then recalculated with AAA, CC and PMC while maintaining the AXB-calculated monitor units and beam arrangement. The dose index values obtained using the four dose calculation algorithms were then compared. The AXB and PMC dose distributions agreed with the bone-equivalent phantom measurements (within ±2.0%); the AAA and CC values were higher than those in the bone-equivalent phantom region. For the spine SBRT plans, PMC, AAA and CC were overestimated compared with AXB in terms of the near minimum and maximum doses of the target and organ at risk, respectively; the mean dose difference was within 4.2%, which is equivalent with within 1 Gy. The phantom study showed that the results from AXB and PMC agreed with the measurements within ±2.0%. However, the mean dose difference ranged from 0.5 to 1 Gy in the spine SBRT planning study when the dose calculation algorithms changed. Users should incorporate a clinical introduction that includes an awareness of these differences.

中文翻译：

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脊柱立体定向放射治疗四种剂量计算算法的剂量学验证。

评估了B型[各向异性分析算法（AAA）和塌陷锥（CC）]和C型[Acuros XB（AXB）和光子蒙特卡罗（PMC）]剂量计算算法在脊柱立体定向放射治疗（SBRT）中的应用。结合水和骨当量体模来评估百分比深度剂量和剂量分布。随后，对 48 名连续接受临床脊柱 SBRT 计划的患者进行了评估。所有治疗计划都是使用 Eclipse 中的 AXB 创建的。TrueBeam 上的处方剂量为 24 Gy，分两次、10 MV FFF。然后使用 AAA、CC 和 PMC 重新计算剂量，同时保持 AXB 计算的监测单元和光束布置。然后比较使用四种剂量计算算法获得的剂量指数值。AXB 和 PMC 剂量分布与骨等效体模测量结果一致（±2.0% 以内）；AAA 和 CC 值高于骨等效体模区域中的值。对于脊柱 SBRT 计划，与 AXB 相比，PMC、AAA 和 CC 分别在目标和危险器官的接近最小和最大剂量方面被高估；平均剂量差异在4.2%以内，相当于1Gy以内。模型研究表明 AXB 和 PMC 的结果与测量值的吻合度在±2.0%以内。然而，当剂量计算算法发生变化时，脊柱 SBRT 计划研究中的平均剂量差异范围为 0.5 至 1 Gy。用户应纳入临床介绍，其中包括对这些差异的认识。